Vehicle spring



Aug, 12 1924- 1,505,036

F. W. LANCHESTER VEHICLE SPRING Filed Oct. 23, 1918 2 Sheets-Sheet 1:NVENTUR FWLancZesZ'w V B ATTORNEY Aug. 12 1924. 1 505036 F. W.LANCHESTER VEHICLE SPRING Filed Oct. 23. 1918 2 Sheets-Sheet 2 AUORNEYPatented Aug. 12, 1924.

UNITED STATES.

FREDERICK WILLIAM LANGHESTER, LONDON, ENGLAND.

VEHICLE SPRING.

Application filed'october 23, 1918. Serial No. 259,452.

To all whom it may concern:

Be it known that I, FREDERICK WVIL IAM LANCHESTER. a subject of the Kingof Great Britain and Ireland, and residing at ll Bedford Square, London,(ll, England, have invented certain new and useful Improvem ents inVehicle Springs, of which the following is a specification.

The present invention relates to an improved system of springs forvehicles, and has for its object to do away with the employment of steelsprings and to enable any desired degree of damjping to be readilyintroduced.

It consists "in brief in the employment of liquid in compression as anelastic medium for absorbing road shock.

It further consists in a means and mechanism for employing liquid incompression as an elastic medium and as a means of damping in thespringing or suspension of vehicles.

It further consists in hydraulic or compressed liquid suspensionapparatus for road or rail vehicles comprising a. specialized pump orreplenisher, actuated-by the motion of the suspension itself, in suchmanner as to automatically generate and maintain the pressure required.7

It further consists in compressed liquid suspension apparatus for roador rail vehicles comprising a replenisher in which a replenishing pistonis rendered functionally operative by the main pressure ram or plungerwhen the extent of motion passes a certain prearranged limit.

It further consists in the springing or suspension mechanism hereinafterdescribed.

In one mode of carrying the present invention into effect as applied tothe suspension of an automobile road vehicle the load at each suspensionpoint, the latter commonly four in number, is taken by a ram or plungerworking in a vertical or nearly vertical cylinder the pressure spacecommunicating with a hydraulic compression chamber filled with a liquidsuch as mineral oil in a state of compression, and by thecompressibility of whcih the freedom of suspension is controlled orconstrained.

Taking more particularly by way of example the front wheel suspension ofan automobile road vehicle the usual axle in common is done away with,and'in its place a cross member is fitted as a rigid part of the asgreat.

chassis. Each wheel is mounted independently on. a short stub axleformed as one limb of an L shaped stamping, whose other limb forms avertical or nearly vertical pivot. The pivot limb is allowed sufficientrange of sliding movement in its bearing. to take up the inequalities ofthe road, and is fitted with a hydraulic ram of comparatively smalldiameter working in a cylinder which is in communication with a pressurechamber of considerable volume. It is desirable to use high pressure inorder to minimize the volume and weight of fluid carried. If for examplethe area of the ram be calculated on the basis of one ton per squareinch the displacement volume will be twice as great as if it becalculated. on a basis of two tons per square inch and the reservoirvolume will need to be four times Assuming one ton per square inch asthe pressure to be employed, as calculated on the static load, thevolume of the reservoir requires to be about one hundred times thenormal (static) ram displacement.

Oil pressure may be pumped up and maintained by engine power in asuitable reservoir or by power taken off a road wheel axle to aboutdouble the normal pressure necessary to support the static load, and inthis case the ram is arranged to trip open a valve or uncover a port toadmit liquid from the said pressure supply at or near the top of itsrange, that is to say in fact when the vehicle (or that'part of itconcerned) is at the lowest point of-an oscillation.

It is well understood that the periodicity of a suspension is related tothe initial linear yield of the resilient system under load. It is usualto allow. a suspension range to total about twice this amount, so thatthe maximum load on any suspension point for which provision is made isabout double the static load. If the oil pressure system is maintainedas stated at twice the static load these conditions will beautomatically complied with by the apparatus described.

It is understood however, that the proportions of the springing and thesupply pressure employed may be varied in accordance with therequirements of the design and to suit varying circumstances.

In. order to secure any desired degree of damping a restricted aperturemay be provided between the cylinder and the fluid compressionreservoir. This aperture'may r be arrangedso that it may be regulated byvalve may be fitted to prevent the: liquid being forced back into, the.pressure supply ed by the ram or plunger itself.

system. In: order. to prevent the cover-running of the ram and injujrytothemechanism a buffer maybe fitted to the suspension as is frequentlydone in the-present da y suspensions in which'stee'l springs are used.

In place of the mechanically driven hydraulic pump as a'meansof'supplying liquid under pressure at thetopof the main cylinder,andpreferablyaxial therewith, a replenisher cylinder maybe arranged ofcomparatively short strokeadapted to be actuat- Passing through apartition between the replenisher cylinder and the main cylinder is arod adapted to be actuated by the main ram if, in its relatively .upwardstroke, it passes a predetermined point. A secondary piston rod passesthrough an aperture in the cover of the replenisher cylinder, and isacted upon by a. spring, by which the replenisher piston is normallymaintained in its lowermost position. The spring box is in permanentcommunication with the main suspension cylinder and hydraulic pressurereservoiriso that, so fardas' the general hydraulic pressure isconcerned, the piston is approximately in equilibrium.

The. replenisher piston takes in oil. on its. underside from a supplyreservoir and pipe and passes this. on its down stroke througha lift orball valve to its upper side. The valves connected with the replenisherare of the ordinary lift type.

The accompanying two. sheets of diagrammatic drawings serve toillustrate by way example. an appl cation of the present inventionto-thefront axle suspension of an automobile road vehicle. Withreference to hes Figure 1 "is .a section; through [a wheel axleandswivel head 'inwhich the: present invention is. employed. I

' Figure 2 is an under View of same.

F1 ure 3 represents in part section a .hy-

drau ic'valve for the admission of oil. underpressure to the hydraulicsuspension system from an ndependent source.

Figure *4: is'a section transverse to'the direction of motion of thevehicle showing a replenisher for the automatic restoration of oil tothe pressure system and also illustrating in greater detail the oilpressure reservoir and its connection to the plunger cylinder.

Figure 5 illustrates, similarly in section,

a simplified construction of replenisher.

Referring-to the figures generally a is the hydraulic plunger or ramwhich carries ithe load; 6 is the hydraulic cylinder: (1 is a tubularaxle formingpart of the chassis construction and constituting the oilpressure reservoir D, the volume of the oil reservoir being determinedby a cap or plug a" brazed into the tube 0 and forming a. pressure tightbulk head therein; 0 is the communication duct between the oil pressurereservoir and the plunger cylinder; F is the face adapted to receive thevalve box or replenisher fitting.

Referring now to the figures in greater detail, the axle tube a isbrazed into a lug 0 (Figure 1) adapted to be bolted to the fore end ofthe chassis longitudinal members. The plun er cylinder 7) forms part ofa stamping, 0 which the lug portion 6 is brazed or otherwisehermetically secured to the end of the tube 0. The plunger (1 which is aclose mechanical fit in the cylinder b, and which can be furnished withhydraulic packing for the prevention of leakage, has formed at its lowerend a head 0: which bears on the blind end of the bored axle lug. 9 Theaxle lug which is conveniently a steel stamping, carries the axle 9 partonly of which is shown, the actuating arm 9 adapted to be coupled to thesteering mechanism, and the coupling arm (7 which is connected by a linkto a coupling arm on the corres )onding head on the other side of thevehic c. The head selected for the purpose of illustration is that onthe steering side of the car, that is, as ordinarily constructed inGrcatlh'itain, the oil side or right hand.

A stiff spring a is provided to cushion the plunger at the upper limitof its motion and a concertina-like leather dust guard g is fittedbetween the axle lug g and the far ing 7) at the head of the plungercylinder t The plunger cylinder 7) and the axle lug g are furnished withferrules b and g respectivelyacting as a safety guard to tie thesuspension motion at its lower limit and one or more leather washers bmay be pro vided to prevent shock in the event of the lower limit of thesuspension motion being reached. Without this provision there arecircumstances in which the wheel and axle T35 assemblage might drop offand become dellltl tached from the car.

In Figure 3 the valve h is adapted to be lifted by contact between. thestem h and the spigot a forming part'of'the plunger a The valve h whenlifted admits oil under pressure from the supply pipe j by way of thefluted valve stem h to thepres sure system, of which the oil duct 6 isshown in the figure. Oil under pressure is fed to the pipe y" from amechanically driven pump andaccumulator at a pressure considerably inexcess of the normal pressure of the suspension system. The feed onlytakes place when the range of the suspensionin the upward directionapproaches within apre-determined distance of its limit, thepro-determined distance depending upon the length of the valve stem 72?.The valve h is restored to its closed position by the spring k and thevalve box is adapted to be bolted to the head of the plunger cylinder 6a hydraulic joint being made as indicated at 6 v Referring now to Figure4, in this figure the oil reservoir D and duct 6 are shown in greaterdetail. A check-nipple e to which access is given by the-plug c isprovided, in order to secure the necessary degree of damping and toperform the function commonly assigned 'tothe fitting termed a shockabsorber. The degree of damping required varies according to thecircumstances in which a car is used and'the check nipple 6 maybewithdrawn by a screw driver inserted through the plug hole 6 andreplaced 'by a nipple having a larger or smaller aperture, as required.In place of the nipplee the design may be varied and a needle valvefitted, in order that the required adustment. may be more readilycarried out; in this case the duct 6 is drilled out of line with theaxis of the plunger cylinder so that the needle valve spindle will notfoul the valve stem or plunger spigot. I v

In the type of replenisher illustrated in Figure 4 a push rod m acts byits head m on a piston m which is restrained by a spring 172* and spigotplate m The disposition is such that when the plunger a rises relativelyabove the position shown in the figure the piston m becomes functionallyoperative and oil'is forced from the upper part of the cylinder n by wayof the ducts n and a into the pressure system, fresh oil being taken inat the lower end of the cylinder n by way of the ducts a if, and n fromthe oil reservoir 0 The oil taken into the cylinder n on the upstroke ofthe piston m is trapped by the suction valve 37 p which is shown as atandem ball valve, and on the return of the piston under the influenceof the spring m the oil so taken in is circulated by way of the valve 39and the duct n from the under to the upper side of the piston m and thepiston and push rod combination m m m is restored to its initialposition ready to become operative again in the event of the plunger aexceeding the normal motion assigned to it. The oil reservoir 0 is atatmospheric pressure and is readily filled through the cap 0 a ventagesuch as indicated by a hole 0 being provided in order to avoid theformation of a vacuum or partial vacuumwhen the oil is drawn off for thereplenishment of the hydraulic system. In some: cases it is preferableto entirely en- 'clo'sethe oil reservoir 0 and to maintain a certainvolume of compressed air in the uppe-rpart of the oil TESQJTVOII, whichmay be ducts r and r and the valve 8 into the hydraulic pressure systemand taking in fresh oil from the oil pressure reservoir through the ductW, the valve 8 and the duct 1 on the down stroke. The cap 9 serves toretain the bush q in position and holes are provided 9 by whichcommunication is established for the flow of oil when the spigot abecomes operative in the manner described. The arrangement --illustratedby Figure 5, though simpler than Figure 4,

cannot be regarded as being as fully effective inasmuch as the area ofthespigot a is deducted from the operative area of the plunger on thereturn stroke for the period during which fresh oil is being taken intothe system through the duct r Under these conditions the spring a inFigure 1 may have to be relied on to prevent the suspension hanging upand thusa far heavier, stiffer spring is necessary than when the systemdescribed with reference to Figure 4 isadopted.

Having-now described my invention, what I claim asnew anddesire tosecure by Letters Patent is a 1. An elastic road wheel. suspension.mechanism including a closed reservoir of relatively large capacityfilled with liquid, a ram of relatively smaller dimensions as comparedwith the reservoir in open. communication with said reservoir and onwhich ram said vehicle rests, said liquid acting as the elastic mediumin said mechanism.

2. Vehicle road wheel suspension mechanism in which liquid incompression inside closed reservoirs is employed as the elastic medium,and in which the main weight of the vehicle is sustained by rams whosecylinders are respectively in communication with the said reservoirs.

3. Vehicle road wheel suspension mechanism in which liquid incompression inside closed reservoirs is employed as the elastic medium,and in which the main weight of the vehicle is sustained by rams whosecylinders are. respectively in communication with theisaidsreservoirsbyway ,of restricted passages.

4. Vehicle Toad swhe'el suspension mechanism in which liquid incompression inside a thrust:

5. :Mechanism e-of the:'ki-nd defined by claim 4 in which thetubularmember is rotatably mounted-omtheram cylinder to permitithewheel axle;to function tor a steering wheel;

6. Vehicle- 'road wheeli suspension mechanismzof thekind defined byclaim 1 in which a: tubular member, external r to and -sliding on aramacylinderf, carries the ram and the 'eroad wheelaxle-relieving theram of all forces: other; than direct thrust. 1

' 7. Vehicle'road wheelsuspensionmechanism oft-he kind defined-"byclaim-2 in which a tubular member, externalrto and slidingon t-he ramcylinder, carries the-ram and the road wvheel axle i relieving the ramof all forces other than direct thrust.

.8. rVeh-icle road-Wheel suspension mecha- 'nism' of the kind definedby-claim 1, in which -the' liquid pressure reservoirs are embodied intheform of-a transverse' tubular member forming a part of a-chassisstructure, the said tubular member carrying at each extremity ahydraulic cylinder relative to which the road wheel-axle-is slidable.

9. 'Vehicle road wheel" suspension mechanism as defined by claim 2 in*which the liquid" pressure reservoirs are embodied in the form-ofatransversetu-bular member forming a part of the vehicle chassis, the ramcylinders being mounted 'at the ends of theztubular member, and:road-wheelr axles slidably mounted on said cylinders.

10; Vehicle roadwheel suspension mechavnisnras defined: by claim 3 inwhich the liquid-pressure reservoirs are embodied in the form of atransverse tubular member forming a part of the vehicle chassis, theramcylinders being mounted at the ends of the tubular member, and roadwheel: axles slidably mounted on said-cylinders.

11. Vehicle road wheel suspension mechanism including a liquid reservoirformed by a transverse tubular member which is part of thevehiclechassis, a hydraulic cylinder secured'to one end of-the tubular memberandhaving-its interior communicating with said reservoir, a secondtubular member mounted on the exterior of said cylinder and carrylngewheelaxle, and a ramsecured to the second tubular member and slidablyengaging said cylinder.

12. Vehicle road wheel suspension mechanism" of the kind defined byclaim 2 includingmeans for-replenishing the liquid in the saidreservoirs operated by" the relatiy e movement of the said rams andcylinders when the said movement passes a prefixed point.

13. Vehicleroad wheel suspension mechanism-of the kinddefined by claim 3including means forreplenishing the liquid in the said reservoirsoperated by the relative movement of the said rams and cylinders whenthe said movement passes a prefixed point.

14. Vehicle road wheel suspension mechanism in which liquid incompression inside closedreservoirsis'employe'd asthe elastic -medium,'and in which the main weight of the vehicle is sustained by rams whosecylinders are respectively in communication with the said first andsecondreservoirs,

-means for replenishing theliquid in the said reservoirs operated by therelative movement of the said rams and cylinders when 'the-said-movement passes a prefixed point, and a-u xiliary pistons operated bythe said ra ms to replenish the liquid in the respective IGSBIVOIIS'each from an external low pressure source.

In testimony whereof I ha e signed my name-to this specification.

FREDERICK WILLIAM LANCHESTI'IR.

